It can't be a 2 milas the S/N range is incorrect (in case anyone was thinking that, I know I was when I first saw it). I'd guess a 3, but damn that's a poor photo to try and determine what it is...
Has to be a six digit, 2 mil, 3 mil, (or 4 or 5). That style S/N on the bolt carrier and piece parts wasn't around terribly long...